RELATED ART
The present invention relates to an electric apparatus incorporating an oscillating circuit portion, and more particularly to an electronic apparatus in which the mounting structure of an oscillating circuit portion is improved to ensure that an oscillating function does not become unstable due to vibration and impact from the outside.
An electronic apparatus for communication such as a specific small power apparatus incorporates an oscillating circuit for generating a high-frequency signal necessary for transmission and reception. In a case where a PLL synthesizer type is adopted as the oscillating circuit of this type, its component elements are a voltage-controlled oscillator (VCO) and a phase-locked loop (PLL). As it has become possible to realize the VCO and the PLL in the form of one-chip ICs, respectively, by the use of the semiconductor integration technology in recent years, as shown in an assembly perspective view of FIG. 4, the oscillating circuit can be arranged by a simple structure in which a VCO circuit 3 and a PLL circuit (IC) 4 are mounted in an oscillating-circuit mounting region 2 on a main board 1, and its surface is covered with a shielding case 5. The main board 1 is a printed circuit board, and a main-circuit mounting region 6 for mounting other main circuit components is generally set on its surface so as to be larger than the oscillating-circuit mounting region 2.
In the mounting structure shown in FIG. 4, since the VCO circuit 3 and the PLL circuit 4 of the oscillating circuit portion are directly mounted on the main board 1, when an external force such as vibration and impact from the outside is applied to the main board 1, the external force is directly transmitted to the VCO circuit 3 and the PLL circuit 4, and can disadvantageously affect their electric characteristics.